MSc (Environmental Sciences), North-West University, Potchefstroom Campus Urochloa mosambicensis and U. panicoides are morphologically very closely related species. The correct identification of these species is often very difficult especially for maize producers because of the lack in knowledge and the subtle differences between the two species. The incorrect identification of U. mosambicensis and U. panicoides grass weed species could lead to using inappropriate herbicides for control and misdiagnosing resistance for these two Urochloa species. The germination characteristics of these species are species specific which is the case of most grasses. The germination trials conducted with U. mosambicensis and U. panicoides during this study showed dormancy and poor germination percentages. Different pre-treatments were evaluated to determine if the germination percentage of these Urochloa spp. could be enhanced and to determine the optimal conditions to conduct germination trials. Their growth patterns in different soil types together with the rainfall patterns were taken into account to calculate the rate of invasiveness and determine when a crop might be threatened by a flush outbreak of these weed species. This was done at three localities (Potchefstroom, Ventersburg and Bethlehem) with different soil types, and including 10 randomised quadrats at each locality and monitoring them every second week for grass seedling emergence. The practice of conservation farming is on the increase in the agricultural sector and with the no-tillage method being adapted by more farmers, it is important to monitor and control weeds. Weeds that once were not a problem are now starting to occur in cropping systems where they compete for nutrients and minerals that potentially lead to yield loss. In this study different herbicide treatments were evaluated to determine the most effective herbicide and the optimum weed growth stage to control these two Urochloa species in the glasshouse. This study focussed on the biology, optimal conditions and control of U. mosambicensis and U. panicoides to address challenges producers experience in cropping systems in the agricultural sector in South Africa. This will contribute to sustainable control of these relative unknown Urochloa species that most probably will become more dominant in years to come. The hypothesis of this study is therefore that the biology of these two Urochloa species is different and that the control measures for these grass weeds are species specific. Masters